Chapter 15 Flashcards
What is included in the somatosensory system?
The cutaneous senses
Proprioception
Kinesthesis
What is the function of skin?
Warning functions
Protects us from bacteria, chemical agents, and dirt from penetrating or bodies
Provides us with information about the stimuli we come into contact with
What is the epidermis?
The outer layer of skin
What is the dermis?
A layer of skin below the epidermis
What are mechanoreceptors?
Receptors that respond to mechanical stimulation
What is a Merkel receptor?
Mechanoreceptor
Located close to the surface of the skin, small receptive field
Slowly adapting fiber, fire as long as the stimulus is on
What is a Meissner corpuscle?
Mechanoreceptor
Located close to the surface of the skin, small receptive field
Rapidly adapting fiber, fires only when the stimulus is applied and removed
What is a Ruffini cylinder?
Slowly adapting fiber that responds continuously to stimuli
Located deep in the skin, large receptive field
Senses stretching of the skin
What is a Pacinian corpuscle?
Rapidly adapting fiber that responds when the stimulus is applied or removed
Located deep in the skin, large receptive field
Responds to rapid vibration and fine texture
What is the medial lemniscal pathway?
Has large fibers that carry signals related to proprioception and perceiving tough
Transmits the signals at a high speed
What is the spinothalamic pathway?
Consists of smaller fibers that transmit signals related to temperature and pain
How does touch reach the cortex?
Signals enter the spinal cord through the dorsal root, either goes through the medial lemniscal or spinothalamic pathways, and then fibers from both pathways cross over to the other side of the body and synapse in the thalamus and then go to the somatosensory cortex
What are the two areas that receive signals from the thalamus?
The primary somatosensory cortex in the parietal lobe
The secondary somatosensory cortex
What is the insula?
Important for sensing light touch
What is the anterior cingulate cortex?
Involed in pain
What is tactile acuity?
The capacity to detect details of stimuli presented to the skin
How do we measure tactile acuity?
Using the two-point threshold
Grating acuity
What is the two-point threshold?
The minimum separation between two points on the skin that when stimulated is perceived as two points
What spacing of Merkel receptors corresponds with a greater tactile acuity?
When they are spaced closer together
What is evidence that Pacinian corpuscles respond to vibration?
They respond very poorly to slow or constant pushing but well to high rates of vibration
What is surface texture?
The physical texture of a surface created by peaks and valleys
What is the duplex theory of texture perception?
Our perception of texture depends on both spatial cues and temporal cues